Reading SynchronizedTextFrame with empty entries causes an error

[muja]

Reproducer

I tried this code:

let path = "foo.mp3";
let mut file = lofty::read_from_path(path)?;
let mut id3v2 = Id3v2Tag::from(file.primary_tag().unwrap().clone());
let sylt_frame = SynchronizedTextFrame::new(
    lofty::TextEncoding::UTF8,
    [b'X', b'X', b'X'],
    lofty::id3::v2::TimestampFormat::MS,
    lofty::id3::v2::SyncTextContentType::Lyrics,
    None,
    vec![(1, "Hello".into()), (2, "".into())],
);

let sylt_frame_byte =
    sylt_frame.as_bytes().expect("should not happen, error constraints are clear");
let sylt_frame_id = lofty::id3::v2::FrameId::new("SYLT").unwrap();
id3v2.insert(lofty::id3::v2::Frame::Binary(lofty::id3::v2::BinaryFrame::new(
    sylt_frame_id,
    sylt_frame_byte,
)));
*file.primary_tag_mut().unwrap() = id3v2.into();
file.save_to_path(path, Default::default())?;

let file = lofty::read_from_path(path)?;
let id3v2 = Id3v2Tag::from(file.primary_tag().unwrap().clone());
let Some(lofty::id3::v2::Frame::Binary(frame)) =
    id3v2.get(&lofty::id3::v2::FrameId::new("SYLT").unwrap())
else {
    unreachable!()
};
SynchronizedTextFrame::parse(&frame.data, frame.flags())?;

Summary

Should parse correctly -- doesn't parse, returns a Error: ID3v2: Encountered invalid data in SYLT frame -- reason is that the terminated byte does not get counted for empty strings.

See #564 for the fix

Expected behavior

Code works

Assets

No response